Telecine - Digital Television and High Definition

Digital Television and High Definition

Digital television and high definition standards provide several methods for encoding film material. Fifty field/s formats such as 576i50 and 1080i50 can accommodate film content using a 4% speed-up like PAL. 59.94 field/s interlaced formats such as 480i60 and 1080i60 use the same 2:3 pulldown technique as NTSC. In 59.94 frame/s progressive formats such as 480p60 and 720p60, entire frames (rather than fields) are repeated in a 2:3 pattern, accomplishing the frame rate conversion without interlacing and its associated artifacts. Other formats such as 1080p24 can decode film material at its native rate of 24 or 23.976 frame/s.

All of these coding methods are in use to some extent. In PAL countries, 25 frame/s formats remain the norm. In NTSC countries, most digital broadcasts of 24 frame/s progressive material, both standard and high definition, continue to use interlaced formats with 2:3 pulldown, even though ATSC allows native 24 and 23.976 frame/s progressive formats which offer the greatest image quality and coding efficiency, and are widely used in motion picture and high definition video production. Nowadays, most HDTV vendors sell LCD televisions in NTSC/ATSC countries capable of 120 Hz or 240 Hz refresh rates and plasma sets capable of 48, 72, or 96 Hz refresh. When combined with a 1080p24-capable source (such as most Blu-ray Disc players), some of these sets are able to display film-based content using a pulldown scheme of whole multiples of 24, thereby avoiding the problems associated with 2:3 pulldown or the 4% speed-up used in PAL countries. For example, a 1080p 120 Hz set which accepts a 1080p24 input can achieve 5:5 pulldown by simply repeating each frame five times and thus not exhibit picture artifacts associated with telecine judder.